Control valve

ABSTRACT

A multi-function valve device for controlling the operation of a pneumatically-driven motor. A spring-biased linkage couples a cam-operated push pin to a valve spool assembly. The valve spool assembly coaxially combines the movable elements of a pressure regulator valve, a run valve, and a park valve into a single unit slidable axially within the valve housing and positioned by the spring-biased linkage. The pressure regulator valve permits an increasing pressure to be applied to a slowed or stopped pneumatic motor, approaching the pressure of the pneumatic source to aid in restarting the motor or to provide the additional force necessary to drive a heavily loaded motor. Automatic park and shutoff functions are also provided.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to pneumatic control valves for use withpneumatically driven motors. In particular, this invention relates to apneumatic control valve for a windshield wiper motor utilizing thecombined park valve, run valve and regulator valve assembly.

2. Description of the Prior Art

It can be appreciated that when a control valve and apneumatically-driven motor such as in U.S. Pat. Nos. 2,678,029 issued toSprague, et al. and 3,257,910 issued to Gates are first activated, thevarious moving elements of each, such as O-rings, etc., have increasedstatic frictional forces associated therewith. In order to overcome theincreased starting frictional forces, an increased amount of airpressure must be initially provided. In valves of the prior art, thisincreased air pressure is supplied by an operator manually setting avalve control cam to a higher pressure position. This produces anincreased value of regulated air pressure sufficient to overcome thestarting static frictional forces and to start the wiper motor. Once thewiper motor achieves a desired operating speed, the operator mustmanually reset the control cam to a normal operating position. It isdesirable that an air-control valve for a windshield wiper motor includea means for automatically providing higher air pressure to overcomeinitial static frictional forces.

Parking of a wiper motor is not automatically provided by prior artcontrol devices such as shown in U.S. Pat. Nos. 2,616,400 issued toSprague, et al. and 3,005,455 issued to Riester, et al. Parking of awiper motor occurs when air pressure is applied to a separate park portof the wiper motor while air pressure is simultaneously applied to therun port of the wiper motor. The wiper motor operates until the wiperblades come to a park position, at which point the wiper motor isstopped. Prior art control devices require that an operator maintain thewiper control in a separate park position until the wipers are locked inthe park position. A desirable feature for a wiper control is for thewiper control to provide means for automatically parking the wiper motorwhen the control is placed in an off position.

Prior art controls for wiper motors have combined a separate airregulator valve and a separate park control valve in one housing. Thecomponents and functions of these valves have been independent of eachother. For example, one prior art control for a wiper motor has an airpressure regulator valve and a park control valve placed next to eachother, but each valve is independently controlled by a separate push pinwhich rides on a separate cam surface of a rotatable operator control.In addition, this type of valve requires that an operator first manuallyposition the control to the park position. After the wiper motor isparked, the operator is required to manually position the control to anoff position. It is desirable that the components of a wiper control beintegrally combined to produce a compact unit which automaticallyincreases air pressure and which automatically parks a wiper motor. Asimilar control device and motor is shown in Gates U.S. Pat. No.3,257,910.

OBJECTS OF THE INVENTION

It is an object of this invention to provide an improved pneumaticcontrol valve for use with pneumatically-driven motors and other usersof controlled pressure pneumatic driving fluids.

It is a further object of the invention to provide an air control valvefor use with pneumatically-driven motors which combines, in a singleassembly, automatic parking and air pressure regulating functions.

It is another object of the invention to provide an air control valveparticularly suited for use with pneumatically-driven windshield wipermotors which provides an automatic parking function when the valve isreturned to the off position following operation.

It is another object of the invention to provide an air control valvefor use with pneumatically-driven motors which automatically providesfor an increasing pneumatic pressure to be applied to a stalled orslowed motor.

It is a further object of the invention to provide a compact,miniaturized air control valve for use with pneumatically-drivenwindshield wiper motors.

SUMMARY OF THE INVENTION

In accordance with these and other objects of this invention, animproved control valve assembly is provided which delivers fluid from asource of high-pressure fluid to run a fluid-driven motor such as isshown in the Riester U.S. Pat. No. 3,005,445. The motor at a given speedhas a predetermined volume rate of flow and a predetermined fluidpressure for operation. Controlled leakage past a pressure regulatorvalve is provided so that when the rate of fluid flow to the motor dropsdue to a slowing or stopping of the fluid-driven motor, the pressure offluid delivered to the fluid-driven motor rises toward the pressure ofthe fluid source. According to one aspect of the invention, an aircontrol valve assembly provides both a run and an automatic park mode ofoperation for a fluid-driven motor such as a windshield wiper motor. Thecontrol valve assembly includes a pressure regulator valve, a two-wayrun valve, and a three-way park valve. The pressure regulator has amovable regulator element and an orificed plug sized to providecontrolled air leakage when the elements are assembled and upon openingof the valve permits relatively unimpeded fluid flow through the valve.The movable elements of all three valves are connected coaxially andmove axially in concert and with respect to each other to variouspositions providing the different modes of operation for thefluid-driven motor. In the off mode, the run valve is closed, and thepark valve is open and is in pneumatic communication with the run valve.In the run mode, the run valve is opened and the regulated air pressureis delivered to the run conduit of the wiper motor. The park valve isclosed and vented to the atmosphere. When the rate of air flow is lessthan a predetermined volume rate of air flow, the valve structurepermits leakage of air through the regulator valve to automaticallyincrease the air pressure delivered to the motor. In the automatic parkmode the run valve remains open to pneumatic pressure and the park valveis opened to the pneumatic pressure. The park valve thus directs air toautomatically park the motor. After the wiper motor is parked,controlled leakage increases the pressure in the valve chamber to thepneumatic source pressure and automatically closes the run valve withpneumatic pressure still applied to both the run port and park port ofthe motor. The control valve of this invention may be connected to awindshield cleaner motor such as that shown in the Riester U.S. Pat. No.3,005,445 by connecting the park port of the valve to the parking valveof Riester and the run port of the valve to the inlet of the pistonresponsive valve mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an enlarged partially-sectional view of an air control valveand cam mechanism showing the valve in an off position.

FIG. 2 is an enlarged, exploded perspective view of some of the movablevalve components removed from the valve housing.

FIG. 3 is an enlarged perspective view of a cam for operating the aircontrol valve.

FIG. 4 is a graph showing the displacement of a cam pin as a function ofcam rotation.

FIG. 5 shows the valve in a first, initially activated position.

FIG. 6 shows the valve in the first phase of the low-range operatingposition.

FIG. 7 shows the valve in the first phase of the mid-range operatingposition.

FIG. 8 shows the valve in the first phase of the park position.

FIG. 9 is an enlarged view showing the relationship of the O-ring 88 tothe park port 94, in the first phase of the park position.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows the essential structural elements of an air control valveassembly 10. FIG. 2 shows the movable components of the air controlvalve in an exploded, perspective view. As will be described below,FIGS. 5, 6, 7, 8 and 9 show the positions of the movable components inthe housing 12 for several different modes of the air control valveassembly 10.

A pressure regulator valve, generally designated 20, is shown in FIG. 1having a regulator valve chamber 22 formed by a bore 24 located at oneend of the housing 12. A reduction in the diameter of the valve chamber22 produces a step 26 in the interior wall of the valve chamber 22 tothe inner bore 24'. A regulator valve plug 28 having a generallycylindrical configuration is press-fit into the chamber 22 so that theend of a longitudinally extending flange portion 30 of the plug 28 mayabut the step 26 if inserted the maximum distance into the valve body.To obtain the proper valve operation, plug 28 is pressed into chamber 22only far enough to provide the desired valve characteristics. The plug28 has a central bore provided therein which forms a regulator valveorifice 32 having an external edge 33 formed between the bore and theexternal face of the plug. The central bore in plug 28 also has acounterbore 29 slightly larger in diameter than orifice 32, forming aninternal edge therebetween. An axially movable regulator valve pinassembly 34 has an elongated shank portion 36 at the end of which islocated a cylindrical regulator valve pin 38 with chamfered surfaces 40and 40'. The diameter of the valve pin 38 permits axial insertion withinthe valve orifice 32. A first chamfer 40 on the regulator valve pin 38is located between the shank portion 36 and a first edge 42. A secondchamfer 40' is located on the valve pin 38 between the distal end of thevalve pin 38 and a second edge 42'. When high pressure air, for example,at 100 p.s.i. from a source (not shown) is provided at the inlet of theregulator valve 20, the inlet being defined by the outermost portions ofthe bore 24, the pressurized air flows through the annular zone betweenvalve pin 38 and valve orifice 32 providing a controlled leakage pastthe regulator valve. Axial movement of pin 38 in the differentoperational modes of the control valve, as shown in FIGS. 1 and 5-8,results in variable cross-sectional area for fluid flow through theregulator assembly 20.

As shown in FIGS. 1, 2 and 5-8, a run valve 50 has a valve means thereinto regulate flow of pneumatic fluid to the run port 70 which may in turnbe connected to the inlet port of for example a windshield wiper motor.Spool end 52 of the spool 54 has an external circumferential groove 56formed therein for receiving and containing O-ring 58. The O-ring 58cooperates with a valve seat 60 to provide a closable valve meansbetween the regulator chamber 22 and a run valve chamber 62. The runvalve chamber 62 is generally defined by bore 64 formed in the centralinterior portion of the housing 12 and the sealing engagement of theO-rings 58 and 88 with the valve seat 60 and bore 64 respectively, asshown in FIG. 1. Spool 54, positioned within bore 64, carries O-rings 58and 88 positioned at the ends thereof and is adapted for axial movementwithin bore 64. Spool end 52 of the spool 54 has a first shoulder 66 anda second shoulder 68 which fit loosely within the bores 24' and 64respectively and serve as guide means for the spool end 52 within therun valve chamber 62. Because of the loose fit of the shoulders 66 and68 and the constricted central portion of the spool 54, air may flow inthe space between the spool shoulders 66 and 68 and the bore 64 and intothe run valve chamber 62. A run valve outlet port 70 is provided by anaperture 71 in the housing 12. The shank 36 of the pressure regulatorvalve 20 is connected to the spool 54 at shoulder 66 and extends theregulator valve pin 38 axially through chamber 22 into its positionwithin bores 29 and 32 of plug 28.

A park valve 80 regulates air to the park port 94 through an aperture 95in valve housing 12. The spool end 84 of the spool 54 has acircumferential groove 86 defined by a third spool shoulder 90 and afourth shoulder 92. Shoulders 90 and 92 serve to guide the spool end 84within the run valve chamber 64. An O-ring 88 contained incircumferential groove 86 provides sealing engagement of spool 54 withthe valve bore 64 and cooperates with aperture 95 as shown in FIG. 9, toprovide a closable valve means between the run valve chamber 62 and thepark port 94. A park valve chamber 82, vented to the atmosphere, isdefined by valve bore 64 and a sealing engagement of O-ring 88 withvalve bore 64 on the side of O-ring 88 opposite run valve chamber 62.Park valve chamber 82 is vented to the atmosphere through vent aperture96.

A cam pin and valve linkage 100 links an operator controlled cam 140 anda cam follower pin 132 with regulator valve 20, run valve 50 and parkvalve 80. The linkage 100 is composed of the first and secondinterengaging hooks 102 and 104, respectively, and a spring 106. Thefirst of said hooks, 102, has a base portion 114 fixed to the fourthshoulder 92 and extension 122 fixed to said base 114 and extending in adirection parallel to the axis of the valve housing 12 and a noseportion 108 fixed to the extension 122 in a direction perpendicular tothe housing 12. A cam pin shoulder 126 fixed to the cam pin 132 supportsthe second of said hooks 104. The base of said second hook 124 has anextension 112 parallel to the axis of the housing 12 and a nose portion118 perpendicular to the axis of the housing 12. The nose portion 118 ofthe second hook 104 abuts the extension of the first hook 122 and thenose portion 108 of the first hook 102 abuts the extension 112 of thesecond hook 104. The cam pin shoulder 126 and the fourth shoulder 92compress a spring 106 which urges the shoulders 126 and 92 apart and thehooks 102 and 104 toward engagement. The linkage 100 is capable ofsliding axially within the bore 64 of the housing 12 and depending uponthe relative forces applied at each end, one by rotation of the cam 140and the other by the imposition of pneumatic forces, primarily againstface 67, can be collapsed to varying degrees to provide the pressureregulation described in detail below.

FIG. 3 shows the features of the surfaces of cam 140. On the back sideof cam 140 are surfaces 142 and 144 which serve as stops, limitingrotation of the cam to about 270°. When the cam is rotated so that thesesurfaces 142,144 abut corresponding projecting portions of housing 130,further rotation of the cam is prevented. The surfaces of cam 140 whichare contacted by cam follower pin 132 are shown in FIG. 1. Engagement ofcam follower pin 132 with cam surface 146 positions the valve in an offposition, pin 132 being urged against cam surface 146 by pneumaticforces against spool surface 67. Engagement with surface 148 moves thevalve to a transition between an off and an on position. Engagement withsurface 150, the peak of the transition region of the cam, moves thevalve to an initially activated position. Engagement with surface 152moves the valve to a position providing minimum regulated pressure bythe valve. Engagement with surface 154 moves the valve to a position ofan intermediate value of regulated pressure from the valve. Engagementwith surface 156 moves the valve to a position providing maximumregulated pressure by the valve assembly. Note that the local peak onthe cam surface in the vicinity of surface 150 serves as a detentpreventing the cam follower 132 from inadvertently rotating the cam byslipping down the steep cam surface 148.

As hereinbelow described, the resilient bias given by spring 106 to thelinkage 100 and air pressure within regulating valve chamber 22 coactwith the position of cam pin 132 to produce the desired air flow.

FIGS. 1, 5, 6, 7 and 8 show the pneumatic control valve in its variousoperational modes.

FIG. 1 shows the control valve in the off position. In this positionthere is no air flowing to either park or run ports of the windshieldwiper motor. Cam pin 132 abuts face 146 of cam 140, as shown in FIG. 3,and pin 132 is as fully extended from the bore 201 in the housing 12 asthe face 146 will permit. In this position, cam pin 132 provides noaxial impetus to the linkage 100. The hooks 102 and 104 of linkage 100are slidably interengaged with the respective noses 108 and 118 of thehooks 102 and 104 abutting the extensions 112 and 122. The pressuresource supplies pressurized air to the bore 24, around the edge 33,through the valve orifice 32 and between the chamfer 40' and thecounterbore 29 to pressurize the regulator chamber 22. At this offposition, the regulator chamber 22 is pressurized to the capacity of thepressure source. The pressure in chamber 22 acts against face 67 tocompress spring 106 and press O-ring 58 upon its seat 60.

FIG. 5 shows the position of the valve components immediately subsequentto an initial activation from the off position by an operator. Cam 140is rotated from the off position corresponding to cam surface 146 to thepeak 150 so that the pin 132 passes over the transition surface 148 toengage the peak 150 of the cam 140. FIG. 5 shows the position of themovable valve components when the cam pin 132 first engages the peak 150of the cam 140. The linkage 100 is shown compressed with the noseportions 108 and 118 abutting the respective bases 124 and 114. Theaxial impetus provided by the transition face 148 of the cam 140 as itis translated in movement through the cam pin 132, the cam shoulder 126,the second hook 104, the base 114 and thence to the park, run andregulator valves 80, 50 and 20 respectively, unseats O-ring 58 from itsseat 60, thereby permitting flow of pressurized fluid into run valvechamber 62.

When O-ring 58 unseats from its seat 60, as shown in FIG. 5, the smallquantity of pneumatic fluid at full source pressure previously stored inthe regulator chamber 22 is admitted to run valve chamber 62 and then torun port 70. Initially, the linkage 100 will be compressed as shown inFIG. 5 because the static frictional forces in the valve and thepneuamtic forces acting against face 67 of spool 54 will be greater thanthe force required to compress the spring 106. As the pneumatic pressurein chamber 22 quickly diminishes, spring 106 will overcome the pneumaticforce against face 67 and extend linkage 100 fully to open the regulatorvalve, thereby increasing fluid flow through the valve.

As the valve components move axially, O-ring 88 passes over aperture 95to close the park port and vent it to the atmosphere through vent 96.Once the run valve 50 is opened and the park port 94 is closed to sourcepressure and vented to atmosphere, the pressure in chamber 22, chamber62 and consequently the pressure applied to run port 70 will risetowards source pressure until it is sufficient to overcome staticfriction in the motor and begin its operation.

As soon as cam 140 is turned to a position at which follower pin 132 isoff peak 150, the regulator pin 38 moves back into the valve orifice 32,restricting full flow from the pressure source. This diminished flowfrom the pressure source is adequate for low speed motor operationbecause the pneumatic wiper motor requires less air pressure foroperation at a low speed than for the initial activation of the motorfrom a parked position.

FIG. 6 shows the relationship of the valve components in this initialphase of the low range operating position for the pneumatic motor. Toobtain this position the operator turns the control shaft keyed to cam140 so that cam follower pin 132 passes to surface 152 of the cam 140.Pin 38 is positioned within orifice 32, and flow through orifice 32 andaround pin 38 is diminished while the flow through the run port 70 isrestricted only by the demands of the motor, so that the pressure inchamber 22 decreases. The relatively lower pressure in chamber 22 actingagainst face 67 then allows spring 106 to extend and move the valvespool 54 axially toward valve orifice 32. The regulator pin 38 thusmoves within orifice 32, the chamfer 40 cooperating with orifice edge 33to provide a variable flow cross section to regulate the output of thevalve. As shown in FIG. 6, O-ring 88 prevents fluid flow from chamber 62to park port 94 and park port 94 remains closed and vented throughaperture 96 to the atmosphere. High peak 150 in the cam 140 also servesas a detent to prevent the cam pin 132 from rotating cam 140 and therebyslipping into the park position abutting cam surface 146.

FIG. 7 shows the valve components in the initial phase of a mid-rangeoperating speed for the pneumatic motor. This position is obtained whenthe operator moves the control shaft keyed to the cam 140 so that thesurface 154 of the cam 140 is engaged with the cam follower pin 132. Asshown in FIG. 7, the cam follower pin 132 is moved in an axial directiontoward the regulator valve plug 28. The other movable valve componentsincluding the valve spool 54, its O-rings 58 and 88 and valve pin 38 arein turn moved axially toward the valve orifice 32. The regulator pin 38has moved as shown so that the chamfer 40 of the regulator pin 38 liesonly partially within the valve orifice 32. Axial movement of pin 38varies the cross-sectional area defined by chamfer 40 and orifice edge33 to vary the flow of air through the valve. Air will continue to flowthrough chamber 22, chamber 62 and into port 70. O-ring 88 maintains itssealing engagement with the interior walls of the valve body 12 and thepark port 94 remains in communication with the venting port 96. Furtherrotation of cam 130 so that cam follower pin 132 engages surface 154 ofthe cam will further extend regulator pin 38 out of the orifice 32 sothat more air may flow, subject to regulation by pneumatic forces onsurface 67 urging contraction of spring 106.

FIG. 8 shows the position of the movable components of the valveassembly during the initial phase of parking the wiper motor. To obtainthis position the operator rotates the control shaft and cam 140 untilthe cam pin 132 following cam 140 engages the cam surface 146. Theinitial phase of the park position is shown in FIG. 8. The pressure inchamber 62 and then in chamber 22 will achieve a moderate equilibriumpressure determined by the inlet restriction formed by the counterbore29 and pin diameter 38, and the demand of the pneumatic motor. Thepneumatic pressure against surface 67 may be such that spring 106 isthen able to force hooks 102 and 104 apart into the position shown inFIG. 8. The noses 108 and 118 of the respective hooks 102 and 104 abutlimiting travel of the valve components. The pressure applied to theopen park port 94 and then to the motor soon stops the movement of themotor and the pressure in chambers 22 and 62 begins to build since airno longer flows out of ports 70 and 94 and air continues to slowly flowinto chamber 22 by controlled leakage of air past valve pin 38. As soonas the pressure in chamber 22 reaches the level at which pneumaticpressure against surface 67 provides the force needed to compress spring106, valve spool 54 moves axially to close O-ring 58 against its seat60, to the position of the valve components shown in FIG. 1. When valvepin 38 is retracted to the position shown in FIG. 1, it is positioned incounterbore 29 which is slightly larger in diameter than orifice 32. Theadditional flow cross section thus provided permits sufficient pressureand flow to be applied to the motor to activate its valve mechanisms anddrive it to its park position.

While the inventors have described their invention in terms of preferredembodiments, it is clear that one of ordinary skill in the art may makechanges within the scope and spirit of this invention.

I claim:
 1. A valve for controlling the pressure and volume rate of flowof a fluid delivered to a utilization device comprising:a valve housinghaving inlet means for receiving fluid at an elevated pressure, a firstoutlet means axially spaced from said inlet means for providing fluid ata regulated pressure and rate of flow to the utilization device, asecond outlet means axially spaced from said first outlet means forproviding fluid pressure to a control means for said utilization device,vent means axially spaced from said second outlet means for selectivelyventing fluid from said second outlet means, and a regulator valvechamber; an axially movable valve spool contained in said valve housinghave a metering means positioned adjacent said inlet means and adaptedto regulate the pressure and flow rate of fluid entering the regulatorvalve chamber in response to axial movement of said spool; first valvemeans positioned on said spool between said regulator valve chamber andsaid first outlet, said first valve means operable by axial movement ofsaid valve spool to open and close a fluid flow path between said inletmeans and said first and second outlet means, second valve meanspositioned on said spool adjacent said second outlet means and slidablyengaging said housing to selectively connect said second outlet means tosaid regulator valve chamber or to said vent; and means to bias saidmovable valve member against fluid forces in said regulator valvechamber to provide a regulating function for said metering means saidsecond valve means isolating said second outlet from said vent meanswhen said first valve means is closed, and said second valve meansconnecting said second outlet to said vent means after said first valvemeans has moved a defined increment between a fully closed position anda fully opened position.
 2. The valve of claim 1 including an actuatormounted within the housing and having a plurality of positions axiallybiasing said movable valve member, and wherein the bias means includes aresilient biased collapsable coupling means located between the actuatorand the movable valve spool such that the actuator positioned in an openposition opens the first valve means and biases the movable valve spoolagainst axially directed pneumatic forces to provide a regulatingfunction for said metering means.
 3. The apparatus of claim 2 whereinthe resilient coupling means includes a linkage resiliently extendableover a limited distance, whereby said metering means adjustablyregulates flow and pressure of fluid into said regulator valve chamber.4. The apparatus of claim 3 wherein the linkage includes a pair ofslidable L-shaped interengaged links surrounded by a spring, said springapplying a predetermined axial extension force upon said interengagedlinks.
 5. The apparatus of claim 2 including a cam for engagement withsaid actuator, the cam with said actuator as a cam follower providingoperative settings for said valve.
 6. The apparatus of claim 1 whereinthe metering means includes a tapered regulator valve pin movable withina bore in said housing to provide a variable area for flow of saidfluid.
 7. The apparatus of claim 6 wherein clearance of pin to bore issized to provide predetermined leakage past said metering means.
 8. Theapparatus of claim 7 wherein said clearance includes different values atdifferent axial positions of the pin such that varying amounts ofpredetermined leakage are obtained depending upon pin position.
 9. Theapparatus of claim 1 wherein the first valve means includes an O-ring onsaid valve spool cooperating with a valve seat on said housing.
 10. Theapparatus of claim 1 wherein said metering means comprises an orificehaving a regulator valve pin axially movable therein, said meteringmeans permitting a predetermined leakage of fluid therethrough when saidmetering pin is fully within said orifice and providing a variable crosssectional flow area when said pin is withdrawn from or protrudes throughsaid orifice.
 11. The apparatus of claim 10 wherein said regulator valvepin is cylindrical with chamfered surfaces at each end thereof tocooperate with said orifice to provide a variable fluid flow crosssectional area depending upon the axial location of said pin within saidorifice.
 12. The apparatus of claim 10 where said orifice has acounterbore therein to provide additional flow cross sectional area whensaid pin is positioned therein.